Hyper Text Caching Protocol (HTCP/0.0) (RFC2756)
Original Publication Date: 2000-Jan-01
Included in the Prior Art Database: 2000-Sep-13
Internet Society Requests For Comment (RFCs)
P. Vixie: AUTHOR [+2]
This document describes HTCP, a protocol for discovering HTTP caches and cached data, managing sets of HTTP caches, and monitoring cache activity. This is an experimental protocol, one among several proposals to perform these functions.
Network Working Group P. Vixie
Request for Comments: 2756 ISC
Category: Experimental D. Wessels
Hyper Text Caching Protocol (HTCP/0.0)
Status of this Memo
This memo defines an Experimental Protocol for the Internet
community. It does not specify an Internet standard of any kind.
Discussion and suggestions for improvement are requested.
Distribution of this memo is unlimited.
Copyright (C) The Internet Society (2000). All Rights Reserved.
This document describes HTCP, a protocol for discovering HTTP caches
and cached data, managing sets of HTTP caches, and monitoring cache
activity. This is an experimental protocol, one among several
proposals to perform these functions.
1. Definitions, Rationale and Scope
1.1. HTTP/1.1 (see [RFC2616]) permits the transfer of web objects
from "origin servers," possibly via "proxies" (which are allowed
under some circumstances to "cache" such objects for subsequent
reuse) to "clients" which consume the object in some way, usually by
displaying it as part of a "web page." HTTP/1.0 and later permit
"headers" to be included in a request and/or a response, thus
expanding upon the HTTP/0.9 (and earlier) behaviour of specifying
only a URI in the request and offering only a body in the response.
1.2. ICP (see [RFC2186]) permits caches to be queried as to their
content, usually by other caches who are hoping to avoid an expensive
fetch from a distant origin server. ICP was designed with HTTP/0.9
in mind, such that only the URI (without any headers) is used when
describing cached content, and the possibility of multiple compatible
bodies for the same URI had not yet been imagined.
1.3. This document specifies a Hyper Text Caching Protocol (HTCP)
which permits full request and response headers to be used in cache
management, and expands the domain of cache management to include
monitoring a remote cache's additions and deletions, requesting
immediate deletions, and sending hints about web objects such as the
third party locations of cacheable objects or the measured
uncacheability or unavailability of web objects.
2. HTCP Protocol
2.1. All multi-octet HTCP protocol elements are transmitted in
network byte order. All RESERVED fields should be set to binary zero
by senders and left unexamined by receivers. Headers must be
presented with the CRLF line termination, as in HTTP.
2.2. Any hostnames specified should be compatible between sender and
receiver, such that if a private naming scheme (such as HOSTS.TXT or
NIS) is in use, names depending on such schemes will only be sent to
HTCP neighbors who are known to participate in said schemes....